This invention relates to real-time measurements of transport of different vapors into a plurality of barrier coatings, and specifically, these measurements are performed using a combination of acoustic wave and optical detection.
Barrier polymers, for example, are used for many packaging and protective applications. As barriers, these materials typically separate a system, such as an electronic component, a part of an engineering structure, or an article of food, from an environment. Often, such polymers are applied as coatings from liquid coating formulations. To adjust viscosity of the formulations, a wide variety of organic solvents are used.
In combinatorial discovery of coating materials for application as barrier coatings, rapid evaluation of permeability of coatings is of primary importance. Transport of vapors in coatings is typically measured by exposing one side of the coating to an analyte vapor, while nitrogen gas sweeps the other side of the coating to a detector. The detector measures the rate that the analyte vapor penetrates the coating. Another method employs the measurement of the amount of an outgassed vapor when a barrier coating is deposited onto a non-permeable substrate and is exposed to a vapor of interest.
Acoustic wave and optical sensors are useful, for example, for quantitation of chemical species by observing the changes in respective detected parameters as a function of analyte concentration. Often, these measurements produce a non-specific sensor response, making the identification of species problematic. To improve selectivity of sensor response, several methods are known, including pattern recognition of responses from several broadly responsive transducers. Other methods involve measurements of several parameters from a single sensor. Velocity and attenuation of an acoustic wave traveling through a sensing film has been measured in a single acoustic wave transducer. Optical measurements have been combined with acoustic wave measurements in chemical sensors. Surface acoustic wave sensor measurements have been combined with direct in situ Fourier transform infrared external-reflectance spectroscopy. Luminescence intensity and the oscillation frequency of a luminescent monomolecular laminated sensing film have been measured from a single acoustic wave transducer. However, these methods suffer from the impossibility of measurements of barrier properties of multiple coating materials toward several vapors of interest.
Thus, there remains an unmet need to provide devices and methods that avoid the need to use a large coating area to obtain measurable signals. There also remains a need to address difficulties in evaluation of multiple coatings simultaneously, and to address difficulties in measuring the permeability of coatings with respect to several fluids, for example, at once.
In one embodiment, a system for determining barrier properties of a barrier coating, comprises: at least one sensor having at least one external surface, the at least one sensor responsive to interactions with a plurality of fluids; at least one barrier coating associated with each sensor, each sensor having initial characteristics and subsequent characteristics each associated with the barrier properties of the coating with respect to each of a plurality of fluids, where the initial characteristics correspond to the barrier coating properties prior to exposure to any of the plurality of fluids and the subsequent characteristics correspond to the barrier coating properties after exposure to at least two of a plurality of fluids, the initial characteristics for each barrier coating associated with an initial optical property and an initial acoustic wave property, and the subsequent characteristics of each barrier coating associated with a subsequent optical property and a subsequent acoustic wave property; an optical characteristic measurement device for measuring the initial optical property and subsequent optical property associated with each barrier coating; an acoustic wave property measurement device for measuring the initial acoustic wave property and the subsequent acoustic wave property associated with each barrier coating; and a computer for determining a first barrier property and a second barrier property of each barrier coating, the first barrier property with respect to one of the two of the plurality of fluids, the second barrier property with respect to the other of the two of the plurality of fluids, the first barrier property and the second barrier property based on the variation between the initial characteristics and subsequent characteristics associated with both the optical properties and the acoustic wave property of each barrier coating.
In another embodiment, a system for determining barrier properties of a barrier coating, comprises: a plurality of sensors each having at least one external surface; a plurality of barrier coatings, each of the plurality of barrier coatings associated with a corresponding one of the plurality of sensors, each sensor having initial characteristics and subsequent characteristics each associated with the barrier properties of the barrier coating with respect to each of a plurality of fluids, where the initial characteristics correspond to the barrier coating properties prior to exposure to any of the plurality of fluids and the subsequent characteristics correspond to the barrier coating properties after exposure to at least two of a plurality of fluids, the initial characteristics for each sensor associated with an initial optical property and an initial acoustic wave property, and the subsequent characteristics of each sensor associated with a subsequent optical property and a subsequent acoustic wave property; an optical characteristic measurement device for measuring the initial optical property and the subsequent optical property associated with each of the plurality of barrier coatings; a acoustic wave property measurement device for measuring the initial acoustic wave property and subsequent acoustic wave property associated with each of the plurality of barrier coatings; a processing device for determining a first barrier property and a second barrier property of each of the plurality of barrier coatings, the first barrier property with respect to one of the two of the plurality of fluids, the second barrier property with respect to the other of the two of the plurality of fluids, the first barrier property and the second barrier property based on the variation between the initial characteristics and subsequent characteristics associated with both the optical properties and the acoustic wave property of each barrier coating; and wherein the subsequent optical property and the corresponding subsequent acoustic wave property associated with each barrier coating are simultaneous measurements.
In still another embodiment, a method for screening for barrier properties of a barrier coating, comprises: measuring initial characteristics associated with at least one barrier coating associated with at least one corresponding sensor responsive to a plurality of fluid, the initial characteristics including an initial acoustic wave property and an initial optical property; exposing each barrier coating to at least two of the plurality of fluids; measuring subsequent characteristics associated with the least one barrier coating, the subsequent characteristics including a subsequent acoustic wave property and a subsequent optical property; determining a first barrier property and a second barrier property associated with the at least one barrier coating with respect to the at least two of the plurality of fluids based on the initial characteristics and subsequent characteristics.
In yet another embodiment, a method for screening for barrier properties of a barrier coating, comprises: measuring initial characteristics associated with at least one barrier coating associated with at least one corresponding sensor responsive to a plurality of fluids, the initial characteristics including an initial acoustic wave property and an initial optical property; exposing each barrier coating to at least two of the plurality of fluids; simultaneously measuring subsequent characteristics associated with the least one barrier coating, the subsequent characteristics including a subsequent acoustic wave property and a subsequent optical property; determining a first barrier property and a second barrier property associated with the at least one barrier coating with respect to the at least two of the plurality of fluids based on the initial characteristics and subsequent characteristics, where the initial characteristics are measured prior to the exposure to the fluids and the subsequent characteristics are measured subsequent to exposure to the fluids.
In another embodiment, a system for determining barrier properties of a barrier coating, comprises: at least one sensor having at least one external surface, the at least one sensor responsive to interactions with a plurality of fluids; a gas-impermeable cell having an interior chamber, the at least one sensor positioned within the interior chamber; at least one barrier coating associated with each sensor, each sensor having initial characteristics and subsequent characteristics each associated with the barrier properties of the coating with respect to each of a plurality of fluids, where the initial characteristics correspond to the barrier coating properties prior to exposure to any of the plurality of fluids and the subsequent characteristics correspond to the barrier coating properties after exposure to at least two of a plurality of fluids, the initial characteristics for each barrier coating associated with an initial optical property and an initial acoustic wave property, and the subsequent characteristics of each barrier coating associated with a subsequent optical property and a subsequent acoustic wave property; a substrate attachable to the gas-impermeable cell so as to seal the interior chamber, wherein the at least one barrier coating is associated with the substrate; an optical characteristic measurement device for measuring the initial optical property and subsequent optical property associated with each barrier coating; an acoustic wave property measurement device for measuring the initial acoustic wave property and the subsequent acoustic wave property associated with each barrier coating; and a computer for determining a first barrier property and a second barrier property of each barrier coating, the first barrier property with respect to one of the two of the plurality of fluids, the second barrier property with respect to the other of the two of the plurality of fluids, the first barrier property and the second barrier property based on the variation between the initial characteristics and subsequent characteristics associated with both the optical properties and the acoustic wave property of each barrier coating.